1. Field of the Invention
The present invention relates to an apparatus for and a method of reading an image wherein an image reading region for selecting a desired condition for processing an original to be read set in a reading device can automatically be set up.
2. Description of the Related Art
An image scanning reading and reproducing system has widely been used in the printing and platemaking fields, for example, for electrically processing image information stored in originals or subjects to be read so as to produce original film plates with a view toward simplifying working processes and improving the quality of printed images.
In an image reading apparatus of the image scanning reading and reproducing system, image information is read by scanning an original to be read, which is contained in an original cassette.
More specifically, when original film plates, which meet various purposes, are produced in the image reading apparatus, a so-called pre-scan operation or process for firstly feeding the original cassette to a reading unit and then setting up conditions (hereinafter called "processing conditions") composed of magnification selection, a set-up of image processing, etc. is carried out. Then, a so-called main-scan operation or process for setting up the optimum processing conditions based on image information obtained by the pre-scan process and reading the image information again in accordance with the processing conditions is performed.
When the main-scan process is carried out after the image information has been pre-scanned in the above-described manner, suitable processing conditions cannot be set up so long as unnecessary information is included in the pre-scanned image information for the setting up of the processing conditions.
In order to avoid such inconvenience, there has been proposed a method of specifying in advance, for example, the size of each of originals to be read contained for every original cassettes, the positions at which the originals are contained in the original cassettes and reading only desired image information in accordance with this specification or a method of displaying image information obtained by the pre-scan process on a monitor and cutting away a desired region by trimming.
In the proposed methods referred to above, however, dedicated original cassettes are required for every original sizes, and the positions of the originals to be contained in the original cassettes must accurately be set up. When the desired region is trimmed, the region to be trimmed by an operator tends to vary, thereby causing a problem that processing conditions cannot be held constant.